body {
    background: #282c34;
}

.frame {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 400px;
    height: 400px;
    border-radius: 3px;
    box-shadow: 1px 2px 10px 0 rgba(0, 0, 0, 0.3);
    background: #4b4841;
}

.center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}